Apparatus and process for ballistic aerosol marking

Abstract

Disclosed is a process for depositing marking material onto a substrate which comprises (a) providing a propellant to a printhead, said printhead having defined therein at least one channel, each channel having an inner surface and an exit orifice with a width no larger than about 250 microns through which the propellant can flow, said propellant flowing through each channel, thereby forming a propellant stream having kinetic energy, each channel directing the propellant stream toward the substrate, the inner surface of each channel having thereon a conductive polymer coating; and (b) controllably introducing a particulate marking material into the propellant stream in each channel, wherein the kinetic energy of the propellant stream causes the particulate marking material to impact the substrate.

What is claimed is:  
     
       1. A process for depositing marking material onto a substrate which comprises (a) providing a propellant to a printhead, said printhead having defined therein at least one channel, each channel having an inner surface and an exit orifice with a width no larger than about 250 microns through which the propellant can flow, said propellant flowing through each channel, thereby forming a propellant stream having kinetic energy, each channel directing the propellant stream toward the substrate, the inner surface of each channel having thereon a conductive polymer coating; and (b) controllably introducing a particulate marking material into the propellant stream in each channel, wherein the kinetic energy of the propellant stream causes the particulate marking material to impact the substrate. 
     
     
       2. A process according to  claim 1  wherein the conductive polymer is a polythiophene. 
     
     
       3. A process according to  claim 1  wherein the conductive polymer is a polythiophene is of the formula                    
       wherein R and R′ each, independently of the other, is a hydrogen atom, an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an arylalkyl group, an alkylaryl group, an arylalkyloxy group, an alkylaryloxy group, a heterocyclic group, or mixtures thereof and n is an integer representing the number of repeat monomer units. 
     
     
       4. A process according to  claim 1  wherein the conductive polymer is a poly(3,4-ethylenedioxythiophene). 
     
     
       5. A process according to  claim 4  wherein the poly(3,4-ethylenedioxythiophene) is formed from monomers of the formula                    
       wherein each of R 1 , R 2 , R 3 , and R 4 , independently of the others, is a hydrogen atom, an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an arylalkyl group, an alkylaryl group, an arylalkyloxy group, an alkylaryloxy group, or a heterocyclic group. 
     
     
       6. A process according to  claim 5  wherein R 1  and R 3  are hydrogen atoms and R 2  and R 4  are (a) R 2 ═H, R 4 ═H; (b) R 2 ═(CH 2 ) n CH 3  wherein n=0-14, R 4 ═H; (c) R 2 ═(CH 2 ) n CH 3  wherein n=0-14, R 4 ═(CH 2 ) n CH 3  wherein n=0-14; (d) R 2 ═(CH 2 ) n SO 3   − Na +  wherein n=1-6, R 4 ═H; (e) R 2 ═(CH 2 ) n SO 3   − Na +  wherein n=1-6, R 4 ═(CH 2 ) n SO 3   − Na +  wherein n=1-6; (f) R 2 ═(CH 2 ) n OR 6  wherein n=0-4 and R 6 =(i) H or (ii) (CH 2 ) m CH 3  wherein m=0-4, R 4 ═H; or (g) R 2 ═(CH 2 ) n OR 6  wherein n=0-4 and R 6 =(i) H or (ii) (CH 2 ) m CH 3  wherein m=0-4, R 4 ═(CH 2 ) n OR 6  wherein n=0-4 and R 6 =(i) H or (ii) (CH 2 ) m CH 3  wherein m=0-4. 
     
     
       7. A process according to  claim 4  wherein the poly(3,4-ethylenedioxythiophene) is of the formula                    
       wherein each of R 1 , R 2 , R 3 , and R 4 , independently of the others, is a hydrogen atom, an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an arylalkyl group, an alkylaryl group, an arylalkyloxy group, an alkylaryloxy group, or a heterocyclic group, D −  is a dopant moiety, and n is an integer representing the number of repeat monomer units. 
     
     
       8. A process according to  claim 1  wherein the conductive polymer is a polypyrrole. 
     
     
       9. A process according to  claim 1  wherein the conductive polymer is a polypyrrole of the formula                    
       wherein R, R′, and R″ each, independently of the other, is a hydrogen atom, an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an arylalkyl group, an alkylaryl group, an arylalkyloxy group, an alkylaryloxy group, a heterocyclic group, or mixtures thereof, wherein R″ can further be an oligoether group, and n is an integer representing the number of repeat monomer units. 
     
     
       10. A process according to  claim 1  wherein the conductive polymer is a poly(3,4-ethylenedioxypyrrole). 
     
     
       11. A process according to  claim 10  wherein poly(3,4-ethylenedioxypyrrole) is formed from monomers of the formula                    
       wherein each of R 1 , R 2 , R 3 , R 4 , and R 5 , independently of the others, is a hydrogen atom, an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an arylalkyl group, an alkylaryl group, an arylalkyloxy group, an alkylaryloxy group, or a heterocyclic group, wherein R 5  can further be an oligoether group of the formula (C x H 2x O) y R 1 , wherein x is an integer of from 1 to about 6 and y is an integer representing the number of repeat monomer units. 
     
     
       12. A process according to  claim 11  wherein R 1  and R 3  are hydrogen atoms and R 2  and R 4  are (a) R 2 ═H, R 4 ═H; (b) R 2 ═(CH 2 ) n CH 3  wherein n=0-14, R 4 ═H; (c) R 2 ═(CH 2 ) n CH 3  wherein n=0-14, R 4 ═(CH 2 ) n CH 3  wherein n=0-14; (d) R 2 ═(CH 2 ) n SO 3   − Na +  wherein n=1-6, R 4 ═H; (e) R 2 ═(CH 2 ) n SO 3   − Na +  wherein n=1-6, R 4 ═(CH 2 ) n SO 3   − Na +  wherein n=1-6; (f) R 2 ═(CH 2 ) n OR 6  wherein n=0-4 and R 6 =(i) H or (ii) (CH 2 ) m CH 3  wherein m=0-4, R 4 ═H; or (g) R 2 ═(CH 2 ) n OR 6  wherein n=0-4 and R 6 =(i) H or (ii) (CH 2 ) m CH 3  wherein m=0-4, R 4 ═(CH 2 ) n OR 6  wherein n=0-4 and R 6 =(i) H or (ii) (CH 2 ) m CH 3  wherein m=0-4. 
     
     
       13. A process according to  claim 10  wherein poly(3,4-ethylenedioxypyrrole) is of the formula                    
       wherein each of R 1 , R 2 , R 3 , R 4 , and R 5 , independently of the others, is a hydrogen atom, an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an arylalkyl group, an alkylaryl group, an arylalkyloxy group, an alkylaryloxy group, or a heterocyclic group, wherein R 5  can further be an oligoether group of the formula (C x H 2x O) y R 1 , wherein x is an integer of from 1 to about 6 and y is an integer representing the number of repeat monomer units, D −  is a dopant moiety, and n is an integer representing the number of repeat monomer units. 
     
     
       14. A process according to  claim 1  wherein the conductive polymer is doped with iodine, molecules containing sulfonate groups, molecules containing phosphate groups, molecules containing phosphonate groups, or mixtures thereof. 
     
     
       15. A process according to  claim 1  wherein the conductive polymer is doped with a dopant present in an amount of at least about 0.25 molar equivalent of dopant per molar equivalent of monomer and present in an amount of no more than about 4 molar equivalents of dopant per molar equivalent of monomer. 
     
     
       16. A process according to  claim 1  wherein either (i) the marking material particles of particulate marking material have an outer coating of a conductive polymer; or (ii) the marking material particles have additive particles on the surface thereof, said additive particles having an outer coating of a conductive polymer; or (iii) both the marking material particles and the additive particles have an outer coating of a conductive polymer. 
     
     
       17. A process according to  claim 1  wherein the marking material particles have conductive additive particles on the surface thereof. 
     
     
       18. A process according to  claim 17  wherein the conductive additive particles are a conductive metal oxide. 
     
     
       19. A process according to  claim 18  wherein the conductive metal oxide comprises (a) titanium dioxide; b) mixtures of titanium dioxide with (i) silicon dioxide, (ii) alumina, (iii) zinc oxide, (iv) antimony oxide, or (v) mixtures thereof; (c) tin oxide; (d) antimony-doped tin oxide; (e) mixtures of aluminum oxide and silicon dioxide; (f) silicon dioxide treated with n-butyl trimethoxysilane; or (g) mixtures thereof.